1. Field of the Invention
The present invention relates to a method for controlling the throughput of notes processed by a high speed currency processing machine. Specifically, the invention relates to the use of asynchronous components with a currency processing machine in order to manipulate both currency feed density and currency speed through the processor.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
High speed currency processors are common in the fields of bulk currency processing and are used by central banks, large commercial banks, print works, cash in transit, and other entities that require the processing of large amounts of currency. In operation, notes that require processing are fed into the high speed currency processing machine by a note feeder. These notes then travel down a high speed conveyor past a number of detectors which detect various characteristics of the note. Based on the note characteristics detected, the note is then routed to any number of pockets for collation. These pockets enable the high speed currency machine to sort notes by fitness level, denomination, origin, authentication, etc
The throughput of the notes in a currency processing machine is limited by the speed that the notes travel through the machine, as well as the distance between individual notes (currency feed density). Further, prior art high speed currency processing machines mechanically or electronically register the speeds of all of the various components (note feeder, conveyor speed, final disposition collection) in order to ensure that the flow of the notes is continuous and that jamming is avoided. This registration of all the components is typically accomplished by using a single large electric motor to drive timing belts and gears that are all registered to operate at fixed relative speeds or electronically do the same. Prior art currency processing machines can be said to use synchronous components, given that they all operate at the same relative speed, speeding up or slowing down relative to each other. In regular operation they wait on a constant speed.
The distance between each note is fixed in prior art machines and is determined by the velocity of the conveyor, the infeed rate of the note feeder, and the length of the note. The ultimate note velocity is limited by the note's ability to proceed in a linear fashion down the horizontal conveyor without folding or bending as it encounters higher wind resistance with increasing speed and its metric notes. The more limp or more worn the note is, as well as the quality of the note, determines what the optimum speed can be before the notes begin to deflect and jam the equipment. However, prior art machines, which are not adjustable, typically operate at a fixed “safe” speed regardless of the quality of the notes. The best throughput achievable by prior art currency processing machines is in the neighborhood of 40 notes per second.
Consequently, the need exists for a method and apparatus for controlling the throughput of notes processed by a high speed currency processing machine. Such invention should allow for increasing note throughput without changing the velocity of the individual notes as they proceed along the note path through the currency processing machine or change the speed of the notes going through or accomplish both of the above. Further, such invention should be able to automatically adjust the throughput of notes through the currency processing machine, depending on the detected note quality of the batch of the notes that are being processed and by the machine having built in the heuristics to remember the incoming source of the notes (i.e., the quality and source and denomination to set initial speed).